The present invention relates to a computer system and a method for assigning a storage device to the computer system and more particularly, to a method for assigning a storage device to a computer in a computer system including a storage subsystem having a fibre channel interface.
As the amount of information treated in a computer system for use in companies, corporations, etc. is drastically increased, the capacity of a storage device such as a disk for storage of data has been increased steadily in these years. For example, a magnetic disk storage system having a capacity of the order of terabytes is very common. With respect to such a disk storage system, there is a technique by which a single storage device subsystem is made up of a plurality of types of logical disks (which will be sometimes referred to merely as disks), e.g., as disclosed in U.S. Pat. No. 5,956,750. Disclosed in the disclosure is, more specifically, a disk subsystem which is made up of disks having different RAID levels such as RAID5 and RAID1 as devices (logical disks) to be accessed by a host computer, or made up of disks having different access rates as actual magnetic disks (physical disks) of logical disks. A user can selectively use the devices according to the access rates of the respective devices.
Appearance of a fibre channel technique as an interface between a host computer and a peripheral device such as a disk has also led to the fact that a plurality of host computers and a plurality of storage devices are connected by a single fibre channel cable to form a computer system. In such a computer system, each of the host computers can directly access any of the storage devices on the fibre channel. For this reason, the computer system can be expected to share data with the respective host computers and to reduce the load of a network, when compared with the prior art wherein each of the host computers has a storage device.